DESCRIPTION: (Applicant's Description) Specific brain regions, such as the nucleus accumbens and ventral tegmentum, are implicated in drug motivation. However, little is known about the role of these regions in human smoking motivation and relapse. This pilot study will recruit 10 smokers (5 male) to participate in 4 experimental functional magnetic resonance imaging (fMRI) assessment sessions. The sessions will manipulate both withdrawal status (24 hr withdrawal or ad lib smoking) and motivational state (neutral vs. anticipation of smoking). The results will reveal the extent to which incentive brain system structures such as the nucleus accumbens are influenced by manipulations of smoking motivation. In addition, smokers will receive nicotine replacement therapy (NRT-combined nicotine patch and nicotine nasal spray) prior to one of the sessions. This will indicate whether common smoking cessation treatments actually reduce activity of incentive system structures when smokers anticipate smoking. Finally, smokers will be exposed to non- pharmacologic incentive stimuli. This is one test of the notion that nicotine withdrawal reduces incentive system activity and thus, reduces pleasurable anticipation in response to non-drug incentives. These findings will make an important contribution to scientific understanding of the mechanisms of effective smoking cessation treatments and contribute to basic scientific understanding of motivation and addictive processes. Finally, they may provide clues to the vital clinical problem of preventing relapse following smoking cessation treatment.